package com.xugongzhang.springcloud.loadbalance;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author X
 * @date 2022/5/28 14:22
 */
@Component
public class MyLb implements LoadBalancer {

    private AtomicInteger atomicInteger = new AtomicInteger(0);

    public final int getAndIncrement() {
        int current;
        int next;
        do {
            current = atomicInteger.get();
            next = current >= Integer.MAX_VALUE ? 0 : current + 1;
        } while (this.atomicInteger.compareAndSet(current, next));
        System.out.println("访问次数：" + next);
        return next;
    }
    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        // 访问的次数对服务实例的数量求余,得到了返回的服务名的下标
        int index = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);
    }
}
